In 1960 there were 300,000 swimming pools in use in the United States and the number was increasing at the rate of 15,000 per year. At the present time there are probably in excess of 500,000 swimming pools. Nearly all swimming pools have some type of water heater which uses some type of fossil fuel. The energy requirement for swimming pools alone is enormous, and costly.
Since most swimming pools are found in warmer climates or used during the summer seasons in northern latitudes, the use of solar energy to heat swimming pools is a natural but largely neglected resource.
Utilization of solar energy for swimming pools has been heretofore thought impractical because of our present preoccupation with attempts to duplicate present fossil fuel heating systems which heat small amounts of water to very high temperatures in a short period of time. Another deterrent has been the lack of materials which can withstand continuous exposure to the sun for long periods of time without rapid deterioration.
There are many solar heaters in use today but they either depend upon transparent top members which become opaque or dirty in time and lose their efficiency, or they are made of materials which lose their structural integrity with long exosure to direct sunlight.